DESCRIPTION: The objective of the proposed research is to identify and resolve molecular mechanisms that coordinate energy balance in mammals. The two focuses of this proposal are a gene specific transcription factor, C/EBPalpha, and one of its targets, the ob gene. The first specific aim will address the question of how mammals selectively express the C/EBPalpha gene in organs that produce, store and mobilize energy. The second specific aim will examine the signaling pathways that regulate the activity of C/EBPalpha and determine how these pathways respond to system-wide hormonal cues. Specific aims 3 and 4 are directed towards the identification of humoral factors that control expression of the ob gene in mature adipocytes and assignment of cis-acting DNA sequences and transcription factors that facilitate transcriptional regulation of the ob gene in response to such factors.